introduction fundamentals of guis - fh...

D I S P L A Y L A BPFORZHEIM UNIVERSITY


Graphical User Interface: Screen Design

Blankenbach / Pforzheim Univ. / www.displaylabor.de / IT / GUI / Nov 2016

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• Introduction

• Fundamentals of GUIs

Overview

• Screen Design : Navigation, Windows, Controls, Text, …

• Evaluating GUI Performance - Features

- Use

- Master: Calculations

Size, color, …

Except for a few slides (), this

chapter is intended for group

work while designing the

GUI project.





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GUI History 11-12 Example: Car Rental

• … 1980 : Keyboard based

• > 1990

mixed keyboard and mouse

graphic elements need more screen

space and high resolution displays

• > 2000 : like 1990 + color

and different OS, internet





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Interaction 15/16

Advantages Disadvantages

Powerful Commands must be memorized

Flexible Requires learning

Appeals to experts Intolerant to typing errors

Conserves screen space Difficult for casual users

• Command Line


Familiar format Consumes screen space

Simplifies information entry Requires careful and efficient design

Requires minimal training Does nit prevent typing errors

• Form Fill-in See 1990





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Interaction 15/16


Utilizes recognition memory May slow experienced users

Reduces interaction complexity Consumes screen space

Aids decision making process May create complex menu hierarchies

Minimizes typing

Aids casual users

• Menu selection


Natural Difficult to implement

• Antromophic Man-man-like interface incl. language dialogue,

touch, eye movements, …





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Interaction 15/16


Faster learning Greater design complexity

Easier remembering Window manipulation requirements

Exploits visual cues Requires icon recognition

Easy error recovery Inefficient for touch typists

(using keyboard without looking on it)

Provides context Increased chance for screen clutter

Immediate feedback

• Direct Manipulation

Replacement of keyed entry by pointing devices

such as mouse, touch screen, joystick, graphics tablet





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Graphic Systems : Advantages 19 - 23

• Symbols are recognized faster than text

see e.g. toolbars, message boxes with information and warning icons

• Fast learning

• Faster use

• Easier remembering (images can be easier remembered than text)

• Exploits visual cues (visual thinking is faster than verbal expressions)

• Provides context





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Graphic Systems : Advantages 19 - 23

• Fewer errors (incl. error boxes, UNDO should be implemented)

• Increased feeling of control

• Less anxiety („Sorgen‟) concerning use mainly for inexperienced users

• More attractive (relevant for skeptical users)

• May consume less screen space

• Replaces national languages

• Easily augmented with text information (Tool-tip-text)

• Low typing requirements (eliminate the need for typing skills)





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Graphic Systems : Disadvantages 19 - 23

• Greater design complexity (symbol and screen design is very important)

• Inconsistency in technique and terminology

e.g. many different symbols etc. exist for the same task

• Not always familiar (as people are trained to numbers and words)

• Number of symbols are more limited by human comprehension than text

• Inefficient for “heavy” keyboard users

• May be inefficient for experienced users

• Not always the preferred style of interaction (not all users prefer graphics)

• May consume more screen space

• Hardware limitations like processing speed and graphic capabilities





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Graphic Systems : Large vs. Small Screen

• Since smartphone and tablets become widespread, GUI design has to

be adapted to smaller screens, less keyboard input and finger touch.

• Many SW has dedicated versions for each device incl. PC

• In consequence, GUI look & feel is more challenging.

5” / 16:9 / 0.4 m

10” / 16:9 or 4:3 / 0.5 m

20” / 16:9 / 0.6 m

Typical screen size / aspect ratio / viewing distance





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Graphic Systems : Same Task vs. Screen Size

Example: Office Application





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Example: Smart Home






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Example: Smart Home






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Example: Smart Home


Example for

commissioning





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• Modern GUIs can run on very different devices:

- Smartphone

- Tablet / Netbook

- Notebook

- PC Monitor

- TVs (some)

• Large variety of screen size: 5” … 55+”

• Portrait (smartphone, tablet) vs. landscape (tablet, notebook, monitor, TV)

• Touch vs. keyboard & mouse input

Challenge: Look & feel the same for “one” product”:

Adapt style guide & different GUIs with same icons, …





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Fundamental Principles (I) 45 - 58

• Accessibility

Systems should be designed to be usable without modification by many users

• Aesthetically pleasing

Visual appeal by grouping and alignment, use of color and graphics

• Availability

Makes all objects available all the time (only good for large sized screens,

not recommended for smartphone and tablets)

• Clarity

An Interface should be easy to understand in terms of elements, text, functions

• Compatibility

Provide compatibility for tasks, similar products, adopt user‟s perspective





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Fundamental Principles (II) 45 - 58

• Configurability

Permit easy personalization of configuration (OPTIONS)

• Consistency

The GUI should look, act and operate the same throughout all tasks:

- Same action should always have the same result

- The function of elements should not change

- The position of standard elements should not change

• Control

- Actions should result form user requests and performed quickly

- Permit users to customize GUI

• Directness

Available alternatives should be visible





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Fundamental Principles (III) 45 - 58

• Efficiency

Minimize hand and eye movements (mouse keyboard, touch: )

• Familiarity

Use familiar concepts and language (real-world metaphors)

• Flexibility

A system must be sensitive to different needs of users:

Experience, knowledge, skills, personal preferences, …

• Forgiveness

- Tolerate common and unavoidable human errors

- Provide constructive messages when an errors does occur

• Operability

Ensure that the system can be used by everybody





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Fundamental Principles (IV) 45 - 58

• Obviousness

A system should be easily learned and understood:

- What to look at

- What and when to do

- Why and how to do it

• Predictability

The user should be able to follow the progression of a task

(Do not bundle or combine action)

• Recovery

- A system should permit command to reverse or undo the action

- Ensure that work is never lost due to an error

• Responsiveness

The system must rapidly respond to an action including acknowledgement





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Fundamental Principles (V) 45 - 58

• Safety

Protect the user form making mistakes, e.g. by reminders, list of choices, …

• Simplicity

Provide an interface as simple as possible:

- Present common and necessary functions first

- Hide things until they are needed

- Provide visual hierarchy

- Provide defaults

- Provide uniformity and consistency

• Trade-Offs

- User requirements have priority over technical requirements

- Final design is based on balancing often-conflicting design principles

(compare Fundamental Principles)





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User Characteristics (I) 95 - 102

• Motivation

- Is the users attitude towards the system positive, neutral or negative?

- Is the motivation high, moderate or low?

• Stress level etc.

- Is the user patient or impatient?

- Shows the user some kind of stress?

- What are the users expectations – are they satisfied?

• User‟s physical characteristics

- Age distribution (classification) and gender

- Education (degrees, …)

- Handedness (87% right-handed)

- Disabilities





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Speed of Interaction 100

Typical values for keyboard Words per minute

Reading

Prose text > 200

Listening 150

Speaking 100

Typewriting

Fast typist > 150

Average typist 60

Two finger typist 40

Handwriting 30

Computer Transcription 30

Copying text 20





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Good Interface & Screen Designs … 127

• Reflect the capabilities, needs and tasks of the users

• Are adapted to hardware

• Achieve business objectives for which it is designed

Good interface design goals: Reduction of

• Visual work

• Intellectual work

• Memory work

• Motor work (mouse, keyboard)

• Minimize burdens imposed by the technology used

Summary of slides

“Fundamental Principles”

Take care of them for

your case studies.





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How to Discourage the User 128

• Unclear caption, wording, …

• Improper objects and graphics

• Misleading headings

• Unnecessary or irrelevant information

• Requests that require backtrack or thinking about previous stuff

• Poor layout of screen objects incl. their placement

• Poor legibility

Summary of slides

“Fundamental Principles”

Take care of them for

your case studies.





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Interaction Starting Area & Arrangements 135

• Provide the starting point in the screen‟s upper-left corner

• Focus user attention on the most important parts of the screen

• Divide information (elements) into units that are meaningful (grouping)

• Provide an ordering of elements including prioritization

• Possible ordering schemes:

Conventional, sequence of use, frequency of use, function, importance

• Form groups that cover all possibilities

• All information that must be compared is visible at the same time

• Only information which is relevant to the user‟s tasks is presented





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Examples of GUIs : Balance & Symmetry 142 - 150

• Balance / Symmetry

• Instability / Asymmetry





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Examples of GUIs : Sequentiality 142 - 150

• Sequentiality

• Randomness





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Examples of GUIs : Simplicity 142 - 150

• Simplicity

• Complexity





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Examples of GUIs : Predictability 142 - 150





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Screen / Windows

• Arrange all necessary object, elements etc. on one screen (if possible) 181

• Prevent scrolling 178

• If more than one screen is used the user should not have to remember

things from one screen to the next 181

• Arrange object in a way that user interaction including reading) starts

in the top left corner

• Windows should always have a title which is descriptive and unique 186





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Screen / Windows : Arrangement of Screen Tasks 298

Sequential : no





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Sequential : yes





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Sequential : yes – optimized by grouping and rearrangement of checkbox

Main Files

Update with changes





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Arranging Windows 397/8

• Overlapping

No window should ever completely hidden !

• Cascading

• Tiled





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Components of Windows 391

Frame

Title bar*

Menu bar

Status bar

Toolbar

Window state

There are (per definition) primary and secondary windows:

- Primary: see above

- Secondary: Common dialogs, message boxes, pop-up windows, …

User area

*: Customization

possible





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Primary Window 400

• Proper usage

- Used to represent an independent application

- Menu, toolbar, status, …

- Divide independent functions into separate primary windows

- Arrange unrelated functions in one window





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Secondary Windows 401

• Proper usage

- For performing supplemental actions

- For presenting frequently or occasionally used windows

- Use objects of operating systems which are well known to the user

• Important Guidelines

- Should typically not appear in the toolbar

- A secondary window should not be as large as the primary window

Common dialogs, message boxes, pop-up windows, …





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Secondary Windows : Common Dialogs 416

open save

color

print





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Secondary Windows : Message Boxes 411

• Proper usage

- Use for presenting brief messages

- Use for requesting specific actions

- Use for tasks that take are easy to be done


- Should typically contain text which can be understood

- Should have icons for emphasizing





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Secondary Windows : Input Boxes 402

• Proper usage

- Use for input of numbers or text

- Use rarely

- Default input can be set in order to minimize user input


- Should typically contain text which can be understood

- Input data should be verified before processing





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Sizing and Placing Windows 415/6

• Number of windows

- Minimize number of windows needed

- Too many windows can be confusing

• Sizing windows

- Windows should be large enough to present all information

- If a window is too large, determine if all information is needed

and/or related or use other objects which are smaller

- Optimum windows size about 12 lines for text

- Avoid scrolling

- Main windows can/should be maximized (full screen)

• Placing windows

- Don‟t hide other windows completely

- Cascading is recommended





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Elements of GUIs : Menus 308 ff

Hierarchical/sequential structure recommended, additional toolbar 312

Level 0

Level 1

File

Open

Save

Options

O1

O2 >> Text

Number





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Elements of GUIs : Menus 308 ff

- Language and consistency acc. user expectations

- Display all or only relevant alternatives

- Cascade menus if necessary

- Delete or grey out inactive items

- Mark active selections

- Maximum of 6 without grouping or up to 20 with grouping (line separators)

- Order acc. importance or alphabetically

- Use keyboard accelerators (F1 for help, CRTL + C for copy, …)

- Order menu items in a useful order (important first, alphabetically, …)

Organisation & Proper use





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Elements of GUIs : Data Field (Text Boxes) 461

• Description: Rectangular shape, single or multi-line

• Purpose: Text to enter (proposal can be displayed)

• Advantages: Flexibility, familiar, little space, rapid reading

• Disadvantage: Requires keyboard, input must be remembered,

not fail save e.g. for databases

• Proper usage: Data that can‟t be categorized or selection is not possible,

text height and font appropriate, black text on light background

can be structured to requested input, e.g. phone number:

466 / - Phone (area / line – direct)





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Elements of GUIs : Command Button (Toolbar similar) 445

• Description: Rectangular shape, label as text or graphics

• Purpose: Start action

• Advantages: Always visible, faster than menu, can be logically ordered

• Disadvantage: Consumes screen space, requires often pointing device

• Proper usage: Size as large as reasonable, use not more than 6 buttons

on a window, arrange buttons logically, use enable and

disable, use descriptive text





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Elements of GUIs : Checkboxes 478

• Description: Small circles filled if selected and label, only one can be chosen

• Purpose: Selection of only one items (compare to Check Box)

• Advantages: Easy to access, easy to compare, preferred by users

• Disadvantage: Consumes screen space, limited number of choices

• Proper usage: For settings or attributes, non-exclusive choices, good for

choices that are discrete, small and fixed in number, choices

which are not easy to remember, choices that never chance

in content

Vertical and horizontal arrangement





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Elements of GUIs : Radio Buttons 468

Vertical and horizontal arrangement

• Description: Small circles filled if selected and label, only one can be chosen

• Purpose: Selection of only one item

• Advantages: Easy to access, easy to compare, preferred by users

• Disadvantage: Consumes screen space, limited number of choices

• Proper usage: For settings or attributes, non-exclusive choices, good for

choices that are discrete, small and fixed in number, choices

which are not easy to remember, choices that never chance

in content





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Elements of GUIs : Combo Box (Drop down) 504

• Description: Rectangular box offering a list of choices

• Purpose: Selection of one (or more) item when space is limited

• Advantages: „Unlimited‟ number of choices, save screen space, shows all

• Disadvantage: Requires action to display list, long lists require scrolling

• Proper usage: Use when screen space is limited, text can also be typed,

highlight selected choice





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Elements of GUIs : List Boxes 493

• Description: Permanently displayed box with a list of attributes,

selection by mouse possible, no text entry

• Purpose: Displays a collections of items

• Advantages: „Unlimited‟ number of choices, elements can be added

• Disadvantage: Requires action to display list, long lists require scrolling

• Proper usage: Items which are not frequently used, items large in number,

highlight selected choice





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Elements of GUIs : Data Input Examples

Things to evaluate: - User input load

- Screen space

- Data to remember

- Database consistent input (no typing errors, …)

Manual registration of attendees at conference etc. by staff





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Elements of GUIs : Data Input Examples

Type Description Good Issue

A Text Box only

B Radio Buttons

and Text Boxes

C List Boxes and

Text Boxes

D

Drop Combo

Boxes and

Text Boxes





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Elements of GUIs : Scroll Bar, Slider 517

• Description: Bar as scale with buttons, optional text boxes, selected by

mouse, drag or click slider, horizontal and vertical arrangement

• Purpose: Setting of a numerical value without keyboard

• Advantages: Visualization of setting, easy to use, better than keyboard input

• Disadvantage: Consumes more screen space than text input, mouse needed,

can be less precise than text (e.g. 15.6789)

• Proper usage: To set an attribute, limited range of possible values





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Elements of GUIs : Progress Indicator

• Description: Rectangular bar that visualizes the progress performed

• Purpose: Provides feedback of processing of a lengthy operation

• Advantages: Better than hour glass

• Disadvantage: Needs some screen space

• Proper usage: Portion of process completed, can be combined with numbers,

can be used in an extra frame to save screen space or

in status bar





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Elements of GUIs : Tabs 521

• Description: Window containing tabbed dividers, navigation between pages

• Purpose: Presentation of information that can be logically organized

into pages or sections

• Advantages: Resembles sheets of paper, effective organization

• Disadvantage: Visually complex

• Proper usage: To present discrete, logically structured information, tab name

should be short & descriptive, do not use for sequential steps

user is familiar with tabs as options settings





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Elements of GUIs : Icons, Index, Symbol 653

• Description: Square graphics, 16 x 16, 32 x 32, 48 x 48, 256 colors

• Purpose: Visualization and icon to click

• Advantages: Saves screen space, graphics more intuitive for users

• Disadvantage: Often not easy to design

• Proper usage: Use common icons, consider cultural and social aspects as

cross, body, …

Now: Draw icon for “save” on paper

Drawings will be clustered and discusses.





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Elements of GUIs : Tool Bar 614

• Description: Icons that can be selected

• Purpose: User interaction by clicking on icon, additional to menu

• Advantages: Speeds up user interaction

• Disadvantage: Only effective with proper icons, consume screen space

• Proper usage: Excerpt of most often used menu items, icons must be

easy to understand and to remember





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Elements of GUIs : Status Bar 614

• Description: Context sensitive messages related to object with focus or

processing tasks

• Purpose: Provides explanatory information, describes use of objects

• Advantages: Easies user information, saves screen space compared

to labels, …

• Disadvantage: Only effective with user training

• Proper usage: Do not use for essential information





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Elements of GUIs : Common Dialogues

• Description: Series of standardized windows provided by OS

• Purpose: User interaction for open, save, print, …

• Advantages: Users are trained to common dialogues, no SW development

• Disadvantage: In some cases not very effective

• Proper usage: Use meaningful adaptation like extension filters for files





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Elements of GUIs : Palette 488

• Description: Series of graphical elements

• Purpose: Selection of one option

• Advantages: Picture aid, easy to compare

choices, consumes less screen

space than text

• Disadvantage: Limited number of choices or use „>>‟, difficult to organize

for scanning efficiency, requires meaningful graphical

representation

• Proper usage: Setting of attributes, properties or values, exclusive choice,

good for discrete elements which are limited and variable in

number, not easy to remember, do not use when text is

clearer than icons





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Elements of GUIs : Controls Selection 549

Choosing the best control for certain tasks and screen space conditions:

Task Best control Limited space

Exclusive choice Radio buttons Drop down list box

Not exclusive choice Check boxes Multiple selection list

box

Setting a value within

a range Bar Text box

Executing an action Command button

or icon Menu





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Elements of GUIs : Data Presentation 227

• Display information always with labels or headings, use also units

• Display information in a useable format e.g. phone numbers, …

+49 7231 28 - 5

• Format information as commonly used, support format in input box

Time: 10:32:15, credit card: 1234 5678 8901 2345

• Break long strings into 3 or 4 digits with blanks in between

see credit card, phone number, …

• Align data into columns

• Organize for top-to-bottom scanning





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Elements of GUIs : Data Justification 228

• Left justify text formats Name: John Doe Name: John Doe

City: Munich City: Munich

• Right justify numeric data Charge: 102.99 Charge: 102.99

Tax: 1.45 Tax: 1.45

• Create a data „ladder‟ Animal: Cat Animal: Cat

Age: 8 Age: 8

Number: 1234 Number: 1234

State: Ge State: Ge

• Create „data statements‟ Cats: 12 12 cats

Dogs: 8 8 dogs





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Elements of GUIs : Data Justification 228





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Example for Numerical Information

Temperature ‚+„ or ‚-„ ?





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Elements of GUIs : Data Representation 424

GUI proper

made but

issue on color

for select and

non-selected

choices

What is

really

selected ?





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Elements of GUIs : Graphical Data Presentation (I) 263

• Graphs are suitable for fast and easy comparison of data

• When charts & graphs? < 3 numbers: words ; 3 – 10: table ; > 5 graph

• Line graph - not more than 5 curves

- use adjacent labels, at least legend

- use solid lines for actual data, dotted for projected

• Bar charts - horizontal or vertical

- vertical typically over time

- horizontal: top information more relevant

• Pie charts - data must add to 100%

- use less than 5 segments, no segment less than 5%

Major types of charts and graphs (see MS EXCEL)





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Elements of GUIs : Graphical Data Presentation (II) 263

• Graphs emphasize data

• Show data not design variation

• Provide proper context for data interpretation (see example)

• Use of axis, scale, labels, legends, units in a proper way

• Fill entire area of graph with data

• Use the appropriate graph (scatter, line, pie chart, …)

• Do not overload graphs with multiple data, a maximum of 5 is recommended

• Use easy to distinguish line coding

• Data lines etc. should be the most visible, use thinner lines for axis and grid





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Elements of GUIs : Graphical Data Presentation (III) 263

Example for proper context for data interpretation

Turn over /B$

2

1

0

2005 2006

Before, after ???

Turn over /B$

2

1

0

2003 2004 2005 2006 2007





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Elements of GUIs : Words and Text 565, 628

• Choosing proper words

- Use short & familiar words in simple language,

- Use only complete words and positive terms

- Use plain and simple proportional fonts with point size of 12 - 14

- Do not use jargon, abbreviations, …

• Sentences and messages

- Must be brief and simple, limited to about 20 words per sentence,

- Must be understandable for all users (education, qualification, …)

- Line length 75 – 100 characters, use proper line spacing

- Emphasize text by position, boxes, bold font, capital letters, …

• Message Boxes

- Title bar must clearly provide the source of the message

- Text must be clear (s.a.) and limited to about 2 to 3 lines

- Icon is often helpful





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Elements of GUIs : Summary

• GUI design is most important to MMI

• Proper GUI saves (less user time, acceptance) money

• User should never „lost‟, HELP is strongly recommended

HELP (or information) via Status Bar, Tool Tip Text, Help file, …

• Response time is mission critical

• If applicable refer to corresponding cultures

• System limitations have to be „compensated‟ by GUI

• Evaluation (see next chapter) is necessary





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Group Work : Case Study V (Bachelor)

Topics for presentation, GUI prototyping and final documentation

- Check your GUI for consistency and recommendations of

“good screen design”.

- Update your GUI and prepare 2 slides: “before after”

- Next lecture: Presentation of

- 1 slide for introduction of case study

- Case Studies IV (~3 slides)

- Case Studies V (~2 slides)

- Updated prototype of your GUI (~ 3 slides)

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